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Conformational Ensembles from Experimental Data
and Computer Simulations
Poster Abstracts
49
16-POS
Board 16
Modelling of the Flexible Protein Histatin 5
Carolina Cragnell
, Marie Skepö.
Lund University, Lund, Sweden.
The existence of functional disordered (unstructured) proteins has been recognized for many
years. However, due to the classical structure-function paradigm, the functional role of
intrinsically disordered proteins has only recently been recognized. Biochemical evidence has
since shown that these proteins are functional, and that the lack of a folded structure is related to
their function.
We would like to present results from a combined experimental and theoretical study, where the
aim is to develop a model for flexible proteins and to relate the lack of structure of the proteins in
solution with their function and structure when adsorbed to surfaces. For this purpose, we are
combining atomistic and coarse-grained modelling, with simulation techniques such as
molecular dynamics and Monte Carlo simulations. The simulations are compared with SAXS
experiments of a model protein (Histatin 5).
We will show simulated scattering curves that are in good agreement SAXS. At high salt
concentration, Histatin 5 behaves as a neutral polymer, and at low salt concentration, a repulsive
peak is obtained at low q. In the latter regime, it is the net charge of the protein that is of
importance for the inter molecular interaction and not the charge distribution. Preliminary results
also indicates that the peptide is more streched out in low pH solutions as well as in prescence of
divalent ions such as Zn2+, Mg2+, and Ca2+, This indicate that electrostatic interactions indeed
are important for Histatin 5 bulk structure.